In general, it is used in the dialysis treatment a blood circuit for extracorporeally circulating the blood of a patient and returning it again into a body of a patient. The blood circuits mainly comprises an arterial blood circuit and a venous blood circuit adapted to be connected to a dialyzer (blood purification means) provided e.g. with hollow fiber membranes. An arterial puncture needle and a venous puncture needle can be mounted on tips respectively of the arterial blood circuit and the venous blood circuit and thus the extracorporeal circulation of the blood can be performed in the dialysis treatment with the puncture needles being punctured to a body of a patient.
A peristaltic blood pump is arranged in the arterial blood circuit and the blood of a patient is adapted to be fed to the dialyzer by driving the blood pump. On the other hand an arterial drip chamber and a venous drip chamber are connected to the arterial blood circuit and the venous blood circuit respectively and thus the blood is returned to a body of a patient after removal of bubbles therefrom.
A priming solution supplying line (physiological saline solution line) is connected to the arterial blood circuit at the upstream side (i.e. arterial puncture needle side) of the blood pump via a T-joint for supplying the physiological saline solution during the priming and the autotransfusion. The dialyzer is structured so that the priming is performed before the dialysis treatment by supplying the physiological saline solution and charging the structural elements such as blood circuits and drip chambers connected thereto with the physiological saline solution and then the physiological saline solution is replaced with blood remained in the blood circuits after the dialysis treatment and finally the remained blood is returned to a patient for performing the autotransfusion. A dialysis apparatus furnished with the priming solution supplying line is disclosed e.g. in Japanese Laid-open Patent Publication No. 2000-93449 (“the '449 Publication”).
In particular the priming operation will be concretely described with reference to FIGS. 14 and 15. A reference numeral 103 denotes a dialyzer functioning as a blood purification means in which a blood flow route for passing blood of a patient therethrough and a dialysate flow route for passing dialysate therethrough. The blood flow route has on its opposite ends a blood inlet port “a” for introducing the blood to be connected to a arterial blood circuit 101 on which a blood pump 104 is arranged and a blood outlet port “b” for discharging the blood to be connected to a venous blood circuit 102. On the other hand the dialysate flow route has on its opposite ends a dialysate inlet port “c” for introducing the dialysate to be connected to a dialysate introducing line 107 and a dialysate outlet port “d” for discharging the dialysate to be connected to a dialysate discharging line 108.
Prior to the dialysis treatment physiological saline solution (priming solution) in a physiological saline solution bag 105 is supplied to the arterial blood circuit 101 via a priming solution supplying line 106 by driving the blood pump 104. In this time the dialyzer 103 is arranged so that the blood outlet port “b” is positioned upward and the blood flow route within the dialyzer 103 and the blood circuit are charged with the physiological saline solution by discharging the physiological saline solution introduced into the dialyzer 103 from the blood outlet port “b” through the blood flow route (see FIG. 14).
Then the dialyzer 103 is arranged upside down with clamping the priming solution supplying line 106 so that the blood inlet port “a” is positioned upward (see FIG. 15). Then after having introduced the dialysate from the dialysate introducing line 107 and passed through the dialysate flow route within the dialyzer 103, the dialysate flow route is charged with the dialysate by discharging the dialysate from the dialysate discharging line 108. Thus the priming of the dialysate flow route has been completed following the priming of the blood flow route.
In usual bubbles in the blood flow route moves upward during the priming operation and thus it is necessary to perform the bubble purging by leading the bubbles toward the venous blood circuit 102 with positioning the blood outlet port “b” upward. On the contrary if the priming would be performed under such a condition (i.e. condition of the blood outlet port “b” positioned upward), the dialysate flows from the top to the bottom of the dialyzer 103 against the moving direction of the bubbles. Accordingly the dialyzer 103 has been arranged upside down so that the dialysate can flow from the bottom to the top of the dialyzer 103 to achieve smooth motion of the bubbles and thus more positive bubble purging.
However, such a priming method has a problem of requiring a long priming duration because of increase of priming operation steps due to requirement of arranging the dialyzer 103 upside down before performing the priming of the dialysate flow route and after the priming of the blood flow route. In addition extension of the priming time (duration) causes other problems of delay of commence of dialysis treatment and thus of increase of burden both for a patient and medical personnel.
For solving these problems there has been proposed a technology e.g. as disclosed in PCT International Publication laid opened under No. WO2006/073166 (“the '166 publication”). In this priming technology, following steps are sequentially performed: an initial introducing step in which a tip of an arterial blood circuit and a tip of a venous blood circuit are connected each other and then the venous blood circuit is charged with priming solution (physiological saline solution) by feeding the priming solution by its own weight, a overflowing step in which the priming solution is introduced into the arterial blood circuit in the normal direction by driving a blood pump in the normal direction and discharged from an overflow line extending from a drip chamber arranged on the venous blood circuit, and a reversely recirculating treatment step in which the priming solution is flowed in a direction reverse to that in the overflowing step by driving the blood pump in the reverse direction. According to the priming method of the prior art it is possible to perform the priming operation with keeping the condition in which the blood inlet port of the dialyzer is positioned upward and to simplify the priming operation and thus to easily achieve an automated priming operation.